Emissions and Particulate Characteristics of Spark-Ignition Engines Fueled with Bioethanol–Gasoline Blends

This article presents the results of research on the effects of various bioethanol concentrations in gasoline blends (E0, E10, E30, E50, E100) and increased fuel dosage (+10% and +20%) on spark-ignition engine performance and exhaust emissions. Experiments were conducted on a chassis dynamometer under strictly controlled laboratory conditions using a MAHA MGT-5 exhaust gas analyzer and a MAHA MPM-4 particulate matter analyzer. Power, torque, carbon monoxide (CO), carbon dioxide (CO2), hydrocarbons (HC), oxygen (O2), and particulate matter emissions were analyzed. It was found that up to a 50% bioethanol content, power and torque remained stable, while with E100, a significant decrease in these parameters was observed, partially offset by the increased fuel dosage. CO emissions systematically decreased with increasing bioethanol content, reaching minimum values at E100, while HC emissions generally decreased. CO2 content did not show clear trends, while O2 levels in the exhaust gas increased with higher ethanol concentrations. Particulate matter emissions were irregular, with the lowest values at E30 for the nominal dose and at E10 for the increased dose. The studies revealed significant nonlinearities in the effect of ethanol concentration on emissions, challenging the common assumption of monotonic changes. The results have practical implications for optimizing the calibration of engine control systems, meeting emission standards, and assessing the potential of bioethanol as a road transport fuel.